Continuous folding of paper or the like



y 12, 1956 c. E. IVES ETAL 3,

l CONTINUOUS FOLDING OF PAPER OR THE LIKE 8 Sheets-Sheet 1 Filed Oct. 15, 1963 /0 Z [0 Z4 b5 9 July 12, 1966 c. E. IVES ETAL 3,260,639

CONTINUOUS FOLDING OF PAPER OR THE LIKE Filed Oct. 15, 1963 8 Sheets-Sheet 2 b gy J06 2'6 L35 4 6 b C. E. IVES ETAL CONTINUOUS FOLDING OF PAPER OR THE LIKE t July 12, 1966 8 Sheets-Sheet 5 Filed Oct. 15, 1963 CONTINUOUS FOLDING OF PAPER OR THE LIKE Q QW b kw July 12, 1966 Filed Oct. 15, 1963 AQ W l 4 1% l RN iwfi i m\ QN 1%\ 3 LQ July 12, 1966 c. E. was ETAL 3,260,639

CONTINUOUS FOLDING OF PAPER OR THE LIKE 8 Sheets-Sheet 5 Filed Oct. 15. 1963 MM r ms y 1966 c. E. was ETAL 3,250,639

CONTINUOUS FOLDING OF PAPER OR THE LIKE Filed Oct. 15, 1963 8 Sheets-Sheet 6 July 12, 1966 c. E. IVES ETAL CONTINUOUS FOLDING OF PAPER OR THE LIKE 8 Sheets-Sheet 7 Filed Oct. 15, 1963 8 Sheets-Sheet 8 C. E. IVES ETAL CONTINUOUS FOLDING OF PAPER OR THE LIKE July 12, 1966 Filed Oct. 15, 1963 United States Patent 3,260,639 CONTINUOUS FOLDING OF PAPER OR THE LIKE Clifford E. Ives, Wilmette, and Rupert J. Straub, Lisle,

151., assignors to United States Gypsum Company, Chicago, 111., a corporation of Illinois Filed Oct. 15, 1963, Ser. No. 316,216 6 Claims. (Cl. 156-594) This invention relates to a method and apparatus for forming longitudinal contours in a continuous web and, more specifically, to a method and apparatus for the continuous formation of longitudinal folds or pleats in an elongated web of paper or other foldable material.

The need For many purposes a need exists for the high-speed continuous formation of longitudinal folds, pleats or the like in relatively-thin webs such as paper or the like. For example, in the formation of a ribbed-gypsum building board, a paper web folded to form longitudinal rib envelopes therein is employed as a paper cover for the rib side.

Various methods and apparatuses have been proposed for the continuous formation of longitudinal contours in continuous webs. One of the primary problems encountered, however, has been the buildup of lateral stresses in the web as it is being longitudinally contoured whereby tearing, wrinkling and other difficulties have 'been encountered, particularly at high speeds. Accordingly, efforts have been made to develop methods and apparatuses to minimize or eliminate such lateral stresses.

For example, in US. Patent 2,494,431 a mechanism is disclosed for the continuous corrugation of paper, which mechanism is specifically designed to avoid as much as possible lateral stresses and disruptive lateral movement in the web. Unfortunately, while such mechanisms have reduced lateral stresses and have successfully processed relatively-strong webs they do not lend themselves to the high-speed contouring of relatively-thin sheets of paper, partly because they involve dragging the web over the convergent contouring surfaces.

It is therefore an object of the present invention to provide a continuous method and apparatus for longitudinally contouring elongated webs which lend themselves to the highspeed processing of relatively-thin sheets. It is a more specific object of the present invention to provide a method and compact apparatus whereby longitudinal webs are continuously folded or pleated with a minimum of lateral stress and movement relative to the contacting surfaces. It is still another object of the present invention to provide a compact apparatus for forming pleats in paper or the like characterized by providing a natural-flow convergent system and positively conveying, not dragging, the paper therethrough. These and other objects of the present invention become apparent as a detailed description thereof proceeds.

Brief description of an embodiment To achieve these objects, a continuous apparatus for forming longitudinal contours, such as folds or pleats, in foldable webs is herewith provided. In one embodiment the apparatus comprises a source of an elongated web which is continuously fed to a convex surface disposed to receive same and to change the direction thereof as it passes thereover, thereby imparting to it a convergent tendency. The apparatus also includes a movable convergent supporting surface which is disposed to receive the web from the convex surface, the supporting surface comprising a plurality of individual, longitudinal, convergently-movable sections adjustably spaced from one another adjacent the web-entry extremity and convergent towards the web-exit extremity.

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A movable convergent gripping surface for the web is also provided in opposed and non-interdigitating relation to the convergent supporting surface and is so disposed that the web passes between the two surfaces without any relative movement between the web and the gripping surface. The gripping surface comprises a similar plurality of individual, longitudinal convergently-movable sections; but these sections have a slip-resistant, web-contacting surface and are sufiiciently spaced from one another to permit accumulation of web material therebetween as the individual sections convergently move. Between the individual sections of the gripping surface, means for contouring the accumulated web portions into desired configurations are disposed.

Means are also provided for driving both the supporting surface and the gripping surface substantially smoothly and in unison so that the web passes therebetween and the resulting contoured web exists therefrom in a smooth, constant stream. A concave surface may also be provided and, if provided, is disposed to receive the contoured web exiting from between the supporting and gripping surfaces and to change the direction thereof as it passes thereover. The concave surface serves in part to nullify the convergent flow of the web.

The drawings The details of this and other particular embodiments of the present invention will become apparent from the description of a specific embodiment thereof hereinafter described in connection with accompanying drawings where- FIG. 1 is an over-all diagrammatic plan view of one embodiment of the apparatus of the present invention, details of which are set forth in subsequent figures;

FIG. 2 is an expanded plan view of a portion of the apparatus at the right of FIG. 1 and shows details adjacent the web-entry extremity;

FIG. 3 is an expanded elevation view of a portion of the apparatus at the right of FIG. 1 and shows additional details adjacent the web-entry extremity;

FIG. 4 is a partly-sectioned view of the multiple rolls constituting the convex surface over which the web passes as it enters the apparatus for the contouring thereof;

FIG. 5 is a section view at line 55 of FIG. 4;

FIG. 6 is a section view of portions of the scissor assembly by means of which the spacing between the individual sections of the supporting surface adjacent the web-entry extremity may be varied, said section view being taken in a direction indicated by the line 6-6 in FIG. 1;

FIG. 7 is a section view along the line 7--7 of FIG. 6;

FIG. 8 is a section view along the line 8-8 of FIG. 7;

FIG. 9 is a partial sectional view taken adjacent the web-entry portion of the apparatus in a direction indicated by the line 9-9 in FIG. 1 and shows how the accumulated web portions between sections of the gripping surface are contoured into desired longitudinal configurations;

FIG. 10 is a partial sectional view similar to FIG. 9 but with less detail and shows progressive contouring of the web at about the midway point, as indicated by the line Ill-10 in FIG. 1;

FIG. 11 is a partial sectional view similar to FIG. 10 and shows the last stages of contouring of the web adjacent the web-exit extremity, as indicated by the line 1111 in FIG. 1;

FIG. 12 shows one of the upwardly-curved or crowned supporting bars for the supporting surface, including the spacers which are used to fix the curvature;

FIG. 13 shows one of the longitudinal profile bars which extend substantially the full length in the spaces between adjacent sections of the gripping surface and which constitute part of the means for controlling the progressive contouring of the paper web;

FIGS. 14 through 20 are section views taken at lines 1414 through 20-20, respectively, of FIG. 13;

FIG. 21 is an expanded plan view of a portion of the apparatus at the left of FIG. 1 and shows details of the apparatus at the web-exit extremity, this plan view being complementary to the plan view of FIG. 2;

FIG. 22 is an expanded and detailed elevation view of a portion of the apparatus at the left of FIG. 1 and shows further details of the apparatus at the web-exit extremity, including the drive means for the apparatus, this elevation view being complementary to the elevation view of FIG. 3; and

FIG. 23 is a diagrammatic view of the drive means for the apparatus, including the load cell which provides an electrical signal responsive to the load on the concave surface at the web-exit extremity and thus responsive to the tension in the exiting contoured web.

General comments re drawings For ease of understanding and simplicity, some nonessential details, e.g., certain nuts, bolts and other fastening means, grease and dust seals, lubrication connections, certain structural details, and the like, have been omitted in the aforementioned figures. Such are considered well within the skill of the art in the light of this disclosure and would serve only to unduly burden the drawings with unnecessary detail. Further in some instances where a particular detail is fully disclosed in one figure, it is not necessarily duplicated in other figures, although it may sometimes be shown in simplified form.

In addition, certain optional apparatus for preliminary web preparation has been omitted. For example, portions of the web may be longitudinally creased so as to form fold-prone indentations or lines therein whereby subsequent contouring at the locations of such indentations is facilitated. Such optional apparatus may, for example, comprise one or more creasing rolls (e.g., steel cylinders with circumferential upraised portions) and opposed hard-rubber backup rolls, between which the web is drawn after being unwound from the supply source thereof and before it passes over the initial convex surface described herein.

For orientation in reviewing the drawings, but not limitation with respect to the protection sought, it should be kept in mind that the particular embodiment described is an apparatus for forming a series of seven parallel pleats in a web of relatively-thin paper which may be of the types adhered to the surfaces of a gypsum building board. It is intended that the pleats are to be subsequently opened up and filled with a calcined gypsum slurry at the time of board manufacture whereby the pleats become paper envelopes for seven longitudinal ribs thereon.

Accordingly, the web may comprise conventional gypsum wallboard paper having an initial width of about 57 inches and a pleated width of about 47% inches. The seven pleats may each be about inch in width with about inch undertuck on each side. The pleats are evenly spaced except for one of the pleats adjacent the edge, which is purposefully located closer to the next pleat (as shown in FIGS. 2 and 21) but need not neces sarily be.

General descriptinFIGURE 1 Referring to FIG. 1, the illustrated embodiment of the apparatus comprises a source 12 of a longitudinallycontinuous paper web 14. Web 14 passes over a slightlyconvex surface 16, the degree of convexity of which is preferably adjustable as further described hereinafter. In passing thereover, the web changes direction substantially, i.e., at least about 30, e.g., about 45 The function of convex surface 16 is to impart a convergent tendency to web 14-, the degree of convergence approximating the actual convergence to which it is subsequently subjected. The convex surface is one of several design features which assure that as the web passes through the apparatus and is contoured, every point on the web travels the same distance. Otherwise, web distortion would result.

After leaving convex surface 16, web 14 passes between a lower, movable, convergent supporting surface 18 and an upper, movable, convergent gripping surface 20 having a high coeflicient of friction, the supporting and gripping surfaces each comprising a plurality of individual, longitudinal, convergently-movable sections.

As shown in detail hereinafter, each of the fifteen individual sections of lower supporting surface 18 and the six individual sections of upper gripping surface 20 comprises a continuous chain suspended on chain sprockets adjacent the web-entry and we'b-exit extremities, the chain having mounted thereon a plurality of small plastic platelets so as to form a transversely-segmented, substantiallycontinuous longitudinal surface. The individual sections of each surface are spaced from one another adjacent the web-entry extremity and gradually converge towards the web-exit extremity.

While most of the longitudinal sections of lower supporting surface 18 are hidden by paper web 14 in FIG. 1, it should be understood that the number and width of sections and the degree of convergence are such that at the web-exit extremity the spaces between the individual sections are reduced to the point of mere mechanical clearance. Thus, a substantially-continuous transverse surface results. In contrast, while the individual sections of upper gripping surface 20 have the same axis of convergence, the number and width of individual sections is such that sufficient space between the sections is provided, even at the web-exit extremity, for the progressive accumulation of longitudinal web portions. These are simultaneously contoured into the desired longitudinal configurations such as pleats, as is described in detail hereinafter.

Advantageously, the spacings between the individual sections of supporting surface 18 and between the individual sections of gripping surface 20 are readily adjustable at the web-entry extremity, whereby considerable operating flexibility is achieved. Accordingly, the spacing of the sections of lower supporting surface 18 may be varied somewhat by adjusting connected handwheels 21a or 21b, which in turn actuate a scissor mechanism to be described hereinafter in connection with FIGS. 68. correspondingly and to maintain approximately the same axis of convergence, the spacing of the sections of upper gripping surface 20 may also be readily changed by means of adjust-able supporting structures to be described hereinafter in connection with FIG. '2.

Means for contouring the accumulated web portions are suspended from a series of fixtures 22 which are supported by transverse bars 24, which in turn are secured at their extremities to side frame 26. The means may comprise a series of longitudinal profile bars and interfitting web guides or straddling rollers which are not shown in FIG. 1 because of the small scale of the drawing but are illustrated in subsequent drawings, e.g., FIGS 9-11 and 1320.

It may appear surprising that while seven pleats are contoured into the web in this embodiment, the upper gripping surface 20 has only six, rather than eight, individual convergent sections. Only six sections are necessary, however, because it has been discovered that the edgemost pleats can be converged by means of a longitudinal series of small cocked rubber training rollers (not shown) which are appropriately spaced immediately outboard of the edgemost contouring means and urge the web convergently. These serve the function of additional convergent sections of the gripping surface. Additional convergent sections may be used, of course, the particular technique employed being a matter of design and/ or cost expediency.

Means are also provided for driving the supporting surface and gripping surface substantially smoothly and in unison by means of a chain and/or gear drive system located at corner 28. The drive means may comprise an electric motor and associated operative connections not shown in FIG. 1 because of the small scale thereof but illustrated in subsequent drawings hereinafter, e.g., FIGS. 21-23.

After the resulting contoured web 14 exits from between the supporting surface 18 and gripping surface 20, it optionally passes over concave surface 30, the degree of concavity of which is preferably adjustable as herein described. As previously indicated, a function of concave surface 30 is to eliminate or nullify convergent tendencies in contoured web 14 and to minimize web distortion. The web then proceeds to further processing, use, or collection, e.g., on takeup roll 32.

To maintain the longitudinal contours in the exiting web, it is important that longitudinal tension be maintained in the contoured web. In the present embodiment, for example, tension in exiting contoured web 14 is maintained at about 130-170 pounds distributed over the width of about 48 inches. Maintenance of longitudinal tension may readily be accomplished by controlling the relative speeds of the folding apparatus as compared with the speed of downstream processing or the speed of takeup roll 32, as further described in detail hereinafter.

Detailed descripti0nFigures 2-23 Referring initially to FIGS. '2 through 5, it is apparent that convex surface 16 comprises a plurality of individual steel cylinders 34 rotatably mounted in side-by-side relationship on curved shaft 36. Shaft 36 is rotatably mounted by means of offset shaft extensions 38a and 38b on frame extension 40. The axes of extensions 38a and 38b are common and substantially tangential to the curved axis of shaft 36 at the center thereof. At the outer extremities of shaft extensions 38a and 3812 are fixedly keyed two positioning plates 42a and 42b, by means of which the axial position of convex surface 16 may be adjustably varied. This is accomplished by means of the arc-slots in plates 42a and 42b, through which pass locking bolts 44a and 44b, respectively. The curvature of shaft 36 is designed so that when web 14 passes over cylinders 34 a convergent tendency is induced therein which approximates the actual convergence of the web resulting from pleat formation. Thus, the web is subject to a minimum of stresses as convergence occurs.

The actual convergence (and, thus, required degree of convexity of surface 16) depends upon a number of variables such as the number and size of pleats, the amount of web material utilized therein as compared with the initial Width of the web, the distance over which the contouring operation occurs and the like. For example, in the present embodiment wherein supporting and gripping surfaces 18 and converge over a distance of about 16 feet, wherein the span of convex surface 16 is about 66 inches, and wherein seven pleats are to be formed in the web as heretofore described, the curvature of shaft 36 is such that the axes of the extremities thereof are displaced from the common axes of shaft extensions 38a and 38b by approximately /2 inch.

For any particular combination of variables, those skilled in the art in the light of the present disclosure can readily determine the required curvature of shaft 36. In practice, the curvature of shaft 36 is designed for the maximum anticipated convergence, and for any particular case less than maximum, convex surface 16 is rotated about axes 38a and 38b until the desired effective curvature and convergence are achieved. Locking bolts 44a and 4412 are then tightened to lock convex surface 16 in place.

Convex surface 16 is designed in the form of a plurality of side-by-side rotatable cylinders so as to minimize sliding or wiping action of the web over the convex surface. As is apparent from a consideration of the geometry of web passage over convex surface 16, there are very slight differences in the speed of rotation of the cylinders 34. If surface 16 were made up of one single solid convex roller, a sliding or wiping action by the Web with respect to the roller surface would result. Use of a plurality of rollers on a curved shaft in the present embodiment permits differences in speed of rotation and minimizes sliding or Wiping action, there-by reducing stresses. Ideally, a large number of rotatable cylinders might be employed. In practice, however, the use of seven rotatable cylinders as shown herein has proved very satisfactory.

With reference to FIGS. 2, 3, 6 and 7, it is apparent that the individual sections of supporting surface 18, which total fifteen -in number, comprise continuous fiattop chains 46 to which are secured, exterior of the sprocket-engaging faces, a series of platelet-s 48. Platelets 48 may comprise a plurality of rectangular strips of Delrin iacetal resin closely spaced so as to form a longitudinally continuous (although segmented) surface. 'In the present embodiment the dimensions of the smoothsurfaced platelets 48 are about 1 /2 inches in the direction of surface travel, 3 /2 inches transverse to the direction of surface travel and about /s inch thick. At the web-entry extremity chains 46 rotate about chain sprocket-s 50 mounted on curved shaft 52. The spacing of sprockets 50 on shaft 52 and thus the spacing of the individual sections of surface 18 is controlled by a scissors assembly shown in FIGS. 6, 7 and 8, which permits the spacing to be varied over a substantial range.

The curvature of shaft 52 takes two factors into consideration. Vertically projected, the curvature approximates the curvature of the web as it leaves convex surface .16. Horizontally projected, the curvature approximates an arc whereby the distances between sprockets 50 and the corresponding respective sprockets at the web-exit extremity remain substantially constant as the spacing of sprockets 50 is varied. Otherwise the chains would tighten or develop slack as the spacing is changed.

While portions of only four sections of the scissors are illustrated in FIG. 6, it should be understood that the scissors includes fifteen of such interconnected sections. In FIG. 6, the center scissor section is shown at the left with the next two adjacent sections connected thereto; and an outermost section is shown at the right. Four intermediate sections are omitted as are all seven sections on the other side of the center section. Generally speaking, the scissors" assembly is symmetrical about the center section except for certain obvious mechanical differences.

The scissors assembly illustrated in FIGS. 6-8 is mounted on transverse structural member 54 by bolts 56 and 58. It comprises transverse cover and support plate *60 to which is spacedly secured sprocket positioning plate '62 my means of elongated bolts with intermediate spacers (not shown). Plate 6 2 has a central circular aperture 64 and a series of progressively-larger transverse slots 66a, 66b, 66c, etc., at spaced transverse intervals on each side thereof, only a portion of one side of plate 62 being show-n in FIG. 6. Plate 62 also has a transverse rectangular groove 68 extending its entire length. Lines through the center of central circular aperture 64, slots 66a, 66b, 660, etc., and groove 68 would approximate the average curvature or crown of web -14 as it leaves convex roll 16.

Sections 70ab, 72a-b, 'Ma-b, 76a-b, etc. of the scissors are centrally pivoted on pivot pins 78, 80, 82 (not shown), 84, etc., which pass through central circular aperture 64 and slots 66a, 66b, 660, etc., and are threaded into slide blocks 86, 88, 90, 92, etc., respectively. The length of the bearing surfaces on pins 78, 80, 82, 84, etc.

is designed so that when the threaded extremities are fully'engaged by the slide blocks, sufficient clearance is present for non-binding pivotal movement of the scissors and for sliding clearance of the slide blocks in transverse groove 68. The slide blocks slide in transverse groove 68 only to the extent permitted by the length of the respective slots. Because aperture 64 does not permit transverse movement of pin 78, slide block 86 and the central axis of scissor sections 70a and 70b are essentially stationary and serve as the anchor point for the remainder of the scissors.

Scissor sections 70b and 7211 are pivotally joined at their respective extremities by pivot pin 94. Similarly scissor sections 72b and 74a; 75b and 76a; 70a and 72b; and 72a and 74b are pivotally joined by pivot pins 9 6, 9'8, 100 and 1102, respectively. The upper opposed faces of the scissor sections are undercut for a substantial distance beyond the pivot pin apertures to form recesses, e.g., recess 104 in FIG. 7, into which downward-depending slotted extensions 106a of longitudinal chain-supporting strips 106 are fitted. These chain-supporting strips, which extend almost the full length of the apparatus and rest on transverse support bars 108 above spacers 110, are thus fanned or moved in and out in an arc-like fashion about their respective pivots adjacent the web-exit extremity as the scissors assembly, including pivot pins 94, 96, 98, etc., are retracted or extended on each side of center point located at pivot pin 78.

Similarly, as best illustrated in FIG. 8, the chain sprockets 50 are moved in or out along curved shaft 52 as the scissors assembly is retracted or extended. The operative connection between the scissors and the sprockets is achieved by means of paired roller bearings 11 4a and 1114b. These roller bearings ride on opposed sides of the sprockets and are rotatably mounted on the slide blocks by threaded pivot pins 116a and 116b, respectively. Thus when the scissors assembly is retracted or extended on each side of center pivot pin 78, the pivot pins on each side thereof, e.g., pins 80 and 84, slide back and forth in their respective slots in plate 62. The geometry of the scissors assembly necessitates, of course, that the slots in plate 62 be made progressively larger as the distance from the center pivot pin 78 increases.

Actuation of the scissors is brought about by rotatably-mounted transverse shaft 118, which extends from one side of the apparatus to the other. It is threaded with opposite-lead threads adjacent its two extremities, as indicated at 11 8a. Shaft 1 18 is rotated by means of hand-wheels 2 1a or 21b (FIGS. 2-3), which are operatively connected to each end of shaft 118. The oppositely-threaded portions of the shaft engage correspondingly-threaded blocks which are fixedly secured to the slide blocks of the outermost sections of the scissors. In FIG. 6, threaded block 120 is shown in dashed outline underneath (and secured to) slide block 9 2. In FIG. 7, threaded block 122 on the opposite side of the scissors assembly can also be seen.

As handwheels 211a or 21b are rotated, thus rotating shaft 118, threaded blocks 120 and 122 move back or forth (in opposite directions) on the threaded portion of shaft 118. This moves the sliding blocks secured thereto (e.g., sliding block 92) and the associated structures, including the roller bearings in contact with the chain sprockets 50, the pivot pins on which the outermost scissor sections are pivoted (e.g., sections 76a and 76b), the remainder of the scissor sections, and the chain supporting strips (e.g., strips 106). Since the center scissor sections 70a-b are anchored by pivot pin 78, the remainder of the scissor sections on each side moves towards or away from the center in unison, depending upon the direction of rotation of shaft 118.

It is apparent from the geometry of the scissors assembly and associated structure that when shaft 118 is rotated the spacing between sprockets 50 and thus the associated chains and attached platelets is uniformly changed to arrive at any selected degree of convergence within the design limitations of the apparatus. Simultaneously, the position of the chain supporting strips I106 is correspondingly changed so as to be centered between adjacent chains 46 and thereby continuously support the platelets 4 8 which slide thereover.

As already indicated, the scissors assembly and shaft 52 on which sprockets 50 rotate are designed so as to conform generally to the curvature or crown in the web exiting from convex surface 16. Chain support strips 106 also conform to this crown, which progressively dissipates to a fiat surface as the web moves towards the web-exit extremity of the apparatus. This is accomplished by controlled curvature of transverse support bars 108 which support the chain support strips 106.

As best illustrated in FIGS. 9 and 12, particularly FIG. 12, transverse support bars 108, eight of which are used in the present embodiment, are mounted on a series of spacers 110, which in turn are mounted on transverse structural members of the apparatus, such as, for example, member -54, as shown in FIG. 7. The center spacer 110, indicated by the letter A in FIG. 12, is the same size for all eight of the transverse support bars 108. The outer spacers indicated by the letters B, C and D in FIG. 12 gradually increase in size towards the web-exit extremity until the curvature of bars 108 is substantially eliminated. This is apparent from the following tabulation which shows the sizes of the spacers 110 at positions A, B, C and D of FIG. 12 for each of the eight bars 113 on the apparatus of the present embodiment:

Height of Spacers 110, Inches Approximate Distance of Bar 113 from Sprockets 50,

Inches Position Position Position Position A B C D (No. of Spacers) (1) (2) (2) (2) Referring to FIGS. 2, 3, 9, 10, 11, 2.1 and 22, it is apparent that the individual sections of gripping surface 20, which total six in number, comprise continuous flattop chains 126 to which are secured, exterior of the sprocket-engaging faces, a series of platelets 128. In the present embodiment, chains 126 are identical with the chains 46 of the supporting surface 18. Platelets 128 are also identical with the Delrin plastic platelets 48 of supporting surface 18 except that, instead of a smooth surface, the web-contacting surfaces of platelets 128 have a high coefficient of friction to impart a positive gripping action thereto. This is readily accomplished by cementing grit, sand paper, emery paper or the like to the smooth surfaces of the Delrin plastic platelets, e.g., 36-grit Carborundum paper. The platelets of gripping surface 20 also differ in that the dimension transverse to the direction of surface travel is 4 inches, rather than 3 /2 inches, except for the section of gripping surface 20 at the top of FIG. 2 which is 2 inches.

At the web-entry extremity, chains 126 rotate about sprockets 130, which are substantially identical to the sprockets 50 of supporting surface 18. Sprockets 130 are rotatably mounted in sprocket supports 132, which in turn are mounted on shaft 134 and adjustably secured thereto by means of set collars 136a and 136b. Shaft 134 is in turn aflixed to frame 26 by mounting brackets 138a and 138b.

The spacing of sprockets 130 with respect to each other is readily adjustable by loosening set collars 136a and 136b and sliding sprocket supports 132 to the desired locations on shaft 134. As previously indicated, the particular spacing selected depends upon the degree of convergence required by the sections of gripping surface 20 to accumulate sufficient excess web material therebetween for formation of the desired longitudinal pleats or other contours.

As best shown in FIG. 9, the platelets 128 of gripping surface 20 ride on top of the web 14 with substantially the entire weight of the gripping surface assembly supported thereon. Accordingly, the platelets of gripping surface 20 conform to the transverse curvature established by supporting surface 18, hereinabove discussed.

The individual sections of gripping surface 20 are guided longitudinally by upper and lower guide bars 140 and 142 which extend the length of the sections of gripping surface 20 and interfit between the vertical sides of chains 126. The ends of guide bars 140 and 142 adjacent the web-entry extremity of the apparatus are secured to sprocket supports 132 by means of bracket 144. Thus, guide bars 140 and 142 are always maintained in alignment with the respective sprockets 130, even when changing sprocket spacing.

The ends of guide bars 140 and 142 adjacent the web exit extremity of the apparatus (as seen in FIGS. 21 and 22) have vertical notches therein which are loosely interfitted over complementary vertical notches in transverse plate 146. Plate 146 is mounted on structural member 148 and the vertical notches therein are aligned with the respective sprockets 150 which are keyed to sprocket shaft 152. Sprocket shaft 152 is rotatably mounted in bearing supports 154 and 156, which are also affixed to plate 146 and structural member 148. Thus, the ends of guide bars 140 and 142 at the web-exit extremity are approximately aligned with the respective sprockets 150.

The loose interfitting of the vertical notches in guide bars 140-142 and plate 146 permits the guide bars to pivot at the notches as the spacing at the web-entry extremity is changed. While sprockets 150 are not designed to pivot axial-1y as the spacings of sprockets 130 are adjusted, the thickness of the sprockets 150, or at least the thickness of the outer sprockets 150, may be undersized with respect to the width of the chain links so that chains 126 will not bind or jump the sprockets when approaching at a slight angle.

The vertical distance between guide bars 140 and 142 is maintained by means of separator plates, which are located at intervals of every several feet. Separator plates 158 illustrate one type which comprise small rectangular steel plates bolted to both guide bars. Separator plate 160 illustrates the other type, and differ from separators 158 in that a vertically-elongated aperture is provided at the center thereof, as shown in dashed lines in FIG. 3. This aperture provides a passage for transverse bar 162 which is mounted on both sides of frame 26 by means of bracket 163 and a similar bracket on the opposite side (not shown). Bar 162 prevents longitudinal, horizontal movement of guides 140 and 142 resulting from frictional drag of chains 126. Since the aperture in separator 160 is elongated vertically, however, the chain guides are free to move vertically, at least to the limit of the aperture.

As supporting and gripping surfaces 18 and 20 progressively converge towards the same point of convergence, web material accumulates between the sections of gripping surface 20. This material is progressively contoured as it accumulates by means of elongated web profile bars, e.g., pleat median strip 164 shown in FIGS. 13-20 and a series of interfitting web guides, e.g., pairs of straddling rollers 166 best shown in FIGS. 9', and 11.

The actual formation of the longitudinal contours or pleats in web 14 is also best shown in FIGS. 9, 10 and 11, which illustrate progressive pleat formation at positions indicated by lines 99, 10-10, and 1111 in FIG. 1. It will be noted from a comparison of FIGS. 9, 10 and 11 that the sections constituting gripping surface 20 progressively converge, the spacing therebetween being suflicient, however, to permit formation of the pleats. At the same time, the sections constituting supporting surface 18 also progressively converge until the gaps therebetween substantially disappear, only mechanical clearance remaining at the web-exit extremity.

Interfitting web guides or straddling tapered rollers 166 are rotatably mounted at periodic intervals, e.g., every 4 /2 to 5 inches, on longitudinal holders 168, which are suspended from fixtures 22 on transverse bars 24. Profile bars or pleat median strips 164 are continuous contoured bars extending almost the entire length of the apparatus. They are anchored between each section of gripping surface 20 adjacent the web-entry extremity only and float on supporting surface 18, the positions thereof at any point being controlled by straddling rollers 166.

As shown in FIGS. 13-20, the profile bars 164 in the illustrated embodiment have minimum height initially, e.g., inch (FIG. 14), and progressively increase to a maximum height, e.g., /8 inch, corresponding to the pleat fold at about midpoint in longitudinal travel (FIG. 16). The bars then progressively diminish somewhat in height towards the end (FIG. 20). The width from the upstream end (FIG. 14) to the midpoint (FIG. 16) is as wide as the desired inside of the top of the pleat. From the midpoint to the downstream end (FIG. 20) the width narrows slightly and the edges are relieved to allow the pleat to fold under its own fiat top.

By careful positioning of rollers 166 -a straddle of profile bars 164, the pleats can be made to fold uniformly and evenly. The rate of convergence of the supporting and gripping surfaces 18 and 20 must, of course, be coordi nated with the contouring means so that approximately the correct quantity of web material is accumulated between the sections of gripping surface 20 to form the pleats.

A tendency of the web material on top of the profile bars 164 to bow upwards may sometimes be encountered. This may be readily remedied by applying flatteners to the web at the top of bars 164. These may take the form of bars, rollers, rolling discs or the like. In the embodiment illustrated, rolling steel discs are employed and are held upright without other support by holders 168 (FIGS. 11, 21 and 22). Longitudinal movement of discs 170 is prevented by, for example, transverse abutting plate 170a shown in dashed lines in FIG. 22.

After pleat formation is complete and the pleats leave profile bars 164, it is sometimes advantageous to flatten the pleats still further. This may be accomplished by similar flattening means, and in the embodiment illustrated, hard rubber flattener rolls 172 are shown on top of certain of the pleats at the web-exit extremity (FIG. 21).

While the illustrated embodiment is specific to the formation of flattened pleats with undertucked sides, it should be understood that the apparatus can readily be adopted to a wide variety of contours. For example, if upraised rib-like structures are desired, such as in FIG. 10, such could be the final profile by obvious design modifications apparent to those skilled in the art in the light of the present disclosure.

After pleat formation is complete, the contoured web may optionally be passed over concave surface 30. This surface may take a form similar to the segmented roll or plurality of rotatable cylinders mounted on a curved shaft which has already been described in connection with convex surface 16 of FIGS. 4 and 5. The design considerations are manifestly similar. Web 14 would, of course, pass over the concave portion rather than the convex portion thereof.

As previously indicated, web 14 should pass over the concave surface with a substantial change of direction, i.e., at least about 30, e.g., about 45. The degree of concavity should be employed which would substantially eliminate convergent tendencies in the web and assure that every point on the web travels approximately the same distance.

Concave surface 30 may be mounted in the same manner as convex surface 16 whereby the degree of concavity is adjustably variable. Accordingly, axes 176a and 1761) of concave surface 30 are rotatably mounted in brackets 178a and 17811 and are keyed to plates 180a and 180b, each having arc slots therein. Locking bolts 182a and 182b lock plates 180a and 1802: to brackets 178a and 178b, thereby adjustably fixing the axes 176a and 176b relative to brackets 178a and 1781;.

As previously indicated, longitudinal tension on exiting web 14 is an important consideration in maintaining pleat integrity. Moreover, tension must not be so excessive as to cause tearing or rupture of the web. Tensioning control means must therefore be provided and may take a variety of forms. In the illustrated embodiment, tension in exiting web 14 is detected by the influence of its vertical component on the load supported by brackets 178a and 17%.

Brackets 178a and 1781) are pivota-lly mounted (adjacent one extremity thereof) on frame extensions 184a and 18412 by means of pivot pins 186a and 186b. The opposite extremity of brackets 178a and 178b rest upon load detection cells 188a and 188b which are mounted on frame extensions 184a and 18417 by means of brackets 190a and 190b, Load detection cells 188a and 18811 are of conventional design and are available commercially. They provide electrical signals responsive to the load carried by the cell, which signal may be electrically combined. Since the combined signal is responsive to the load and the load in turn is a function of the tension in exiting web 14, the electrical signal provides a convenient means of controlling tension.

For example, tension in exiting Web 14 of the illustrated embodiment is readily varied by changing the relative speed of surfaces 18 and 20 as compared with takeup roll 32. An incipient increase in the speed of takeup roll 32 or an incipient decrease in the speed of surfaces 18 and 20 tends to increase tension in exiting Web 14. Conversely, an incipient decrease in the speed of takeup roll 32 or an incipient increase in the speed of surfaces 18 and 20 tends to decrease tension in exiting web 14. Thus, tension is conveniently controlled by employing the combined electrical signal from load 188a and 18% to control the speed of take-up roll 32 and/ or the speed of surfaces 18 and 20 techniques Well known to those skilled in the art of speed cont-r01. In the illustrated embodiment, the electrical signal is employed to control the speed of the drive means for surfaces 18 and 20, as hereinafter set forth.

An important and advantageous feature of the illustrated embodiment is the fact that surfaces 18 and 20 are chain assemblies in contrast to alternatives such as flexible conveyor belts or the like. Chains give positive, non-resilient, non-slip drive control Without introduction of problems associated with momentary stretching of the conveyor means or the like. Moreover, movement of a plurality of structures, such as opposed surfaces 18 and 20, can be positively and mechanically coordinated.

Chains do, however, introduce problems of their own, the one of primary concern herein arising from the fact that the true pitch line of a chain sprocket is a polygon of as many sides as there are sprocket teeth. During the passage of each tooth, the distance of the center line of the chain from the center of the sprocket varies. Thus if the sprockets rotate at a constant angular velocity, the chain strand thereb'etween moves With a fluctuating or jerky movement.

An obvious solution would be the use of very-large sprockets with many teeth so that the polygonal pitch line approaches a circle. While sprocket coordination is readily achieved, the requirement of compactness obviates for many purposes, including the present embodiment, the use of very-large sprockets. Accordingly, a

special drive means is employed for surfaces 18 and 20 which retains the smooth, non-jerky motion characteristic of very-large sprockets with many teeth and yet permits the use of relatively-small sprockets with relatively-few teeth. This drive means is best illustrated in FIGS. 21-23.

FIG. 23 is a simplified, diagrammatic perspective which shows the drive means with greater clarity than is possible in detailed FIGS. 21 and 22. Whereelements in FIG. 23 correspond to actual elements in FIGS. 21 and 22, the relationship is indicated by the use of the same identifying numbers, except that in FIG. 23 the identifying number is followed 'by a prime mark.

The primary energy source for the apparatus is electric motor 192, the output shaft of which is coupled via coupling 194 to speed-reducer 196. Electric motor 192 may advantageously be an adjustable speed electric motor with electronic speed control, wherein only minute currents are required for the speed setting potentiometer circuit. The primary control signal to the speed setting potentiometer circuit is based on the output signal of load cells 188a and 188b, previously discussed, whereby control of the tensioning of exiting web 14 is established, as is apparent hereinafter.

The output shaft 198 of speed reducer 196 has keyed thereto a very-large sprocket 200' with many teeth, the pitch line of which approximates a circle for all practical purposes. Sprocket 200' drives chain 202, the slack in which is taken up by slack control sprocket 204. The position of sprocket 204 is adjustable by means of pivotal suspension bracket assembly 206 and positioning bolt and bracket assembly 208.

Chain 202 rotates sprocket 210 which is keyed to rotatable shaft 212. The sprockets for chains 46 of supporting surface 18 are keyed to shaft 212 and are driven thereby. These sprockets are hidden in FIGS. 21 and 22 but are diagrammatically illustrated in FIG. 23 by rollers 213. As previously indicated, there are fifteen of these sprockets on shaft'212 and they are located so that substantially no gaps are present between platelets 48 of the chains 46 of adjacent sections of surface 18. Since chains 46 (except the center chain) are disposed at progressively increasing angles to their respective sprockets as the distance from the center sprocket increases, the tln'ckness of outer sprockets must be undersized so that the chains will not jump off the sprocket or bind thereon.

Gear 214 is also keyed to shaft 212 'and is rotated thereby. Gear 214 is part of gear train comprising gears 214, 216, 218 and 220, the latter gear being adjustably s'ecurable t-o sprocket shaft 152 by means of clamping means 222. Clamping means 222 permits coordination of the angular relationship of the sprocket teeth of the sprockets on sprocket shafts 152 and 212. As those skilled in the design of chain drives recognize, such sprocket coordination minimizes relative movement between the opposed platelets of supporting surface 18 and gripping surface 20.

The angle at which the pulling strand of chain 202 leaves sprocket 214 is also important in achieving smoothness of movement of surfaces 18 and 20. As those skilled in the design of chain drives will also recognize, the disengagement of the teeth of sprocket 214 from chain 202 must be coordinated with the engagement of chains 46 and 126 by the sprocket teeth of the sprockets on shafts 152 and 212. With such coordination a compensatory system is established whereby the angular velocities of the small sprockets, i.e., the sprockets on shafts 152 and 212, vary just sufficiently so that chains of supporting and gripping surfaces 18' and 20 move steadily and smoothly in unison. This requires, of course, that motor 192 be operating at a substantially-constant speed and thus large sprocket 200 be rotating at a sub-' stantially-constant angular velocity.

Recapitulation From the'above description it is apparent that the objects of the present invention have been achieved. Specifically, a continuous method and apparatus are provided for longitudinally contouring elongated webs which lend themselves to the high-speed processing of relativelythin sheets. The entire apparatus is designed from start to finish to achieve a relatively-stress-free natural flow convergent system wherein the paper is positively conveyed along natural flow lines with a minimum of frictional drag or contact with non-moving surfaces. The apparatus is versatile and compactly designed.

Additional refinements may be incorporated but have been omitted in the specific embodiment described above, because such have been found to be unnecessary. For example, the downstream portion of supporting surface 18 might be designed so as to have a concave profile complementary' to concave roller 30. Further, the curvature of sprocket support shaft 52 and supporting surface 18 might be adjustably designed so that the curvature thereof can be adjusted to match the curvature of web 14 whenever the convexity of convex roll 16 is changed. These and other obvious refinements are considered unnecessary and not economically justifiable, although they are well within the skill of the art in the light of the present disclosure.

As aforementioned, certain features have been omitted from the drawings in the interest of simplicity of illustratioh and ease of understanding. For example, additional means for compensating for eventual stretching of the various chains and for sprocket wear and the like are included in the present specific embodiment but have been omitted from the drawings. Such are not considered part of the present invention and are considered within the skill of the art.

It should be understood that while the method and apparatus of the present invention have been described with particular reference to certain specific embodiments, such reference is merely illustrative, and the inventive concept is not necessarily limited thereto. Many alternative embodiments and modifications will be apparent from the above description to those skilled in the art. Such other alternatives are considered within the spirit and scope of the present invention, and coverage thereof is intended by this application.

Having described the invention, what is claimed is:

1. Continuous apparatus for forming longitudinal contours in an elongated web of material comprising:

(a) means for supporting a source of a longitudinallycontinuous web;

(b) opposed first and second non-interdigitating assemblies disposed to receive said web therebetween,

(1) said first assembly comprising a plurality of individual, longitudinal, convergently-movable sections with web-engaging surfaces, said sections being spaced from one another adjacent the web-entry extremity and convergent towards the web-exit extremity;

(2) said second assembly comprising a plurality of individual, longitudinal, similarly-convergently movable sections having slip-resistant, web-gripping surfaces which bear against and frictionally grip web portions disposed against the web-engaging surfaces of said first assembly so that no substantial relative movement between the web portions and said web-gripping surfaces occurs;

the individual sections of at least one of said assemblies being sutficiently spaced from one another to permit accumulation of web portions therebetween as the opposed sections of .both assemblies convergently move, the disposition of respective opposed sections being non-interdigitating;

(c) fixed means disposed between said sufliciently spaced sections for contouring accumulated web portions into desired configurations;

(d) means for driving said first and second assemblies substantially smoothly and in unison whereby the contoured web exits therefrom in a constant stream; and

(e) means for maintaining longitudinal tension in the exiting contoured web.

2. The apparatus of claim 1 wherein said means for contouring the accumulated web portions comprise longitudinal profile bars, and interfitting web guides associated with said profile bars.

3. Continuous apparatus for forming longitudinal contours in an elongated web of material comprising:

(a) means for supporting a source of a longitudinallycontinuous web;

(b) opposed first and second non-interdigitating assemblies disposed to receive said web therebetween,

(1) said first assembly comprising a plurality of individual, longitudinal, convergently-movable sections with web-engaging surfaces, said sections being spaced from one another adjacent the web-entry extremity and convergent towards the web-exit extremity;

(2) said second assembly comprising a plurality of individual, longitudinal, similarly-convergently-movable sections having slip-resistant, web-gripping surfaces which bear against and frictionally grip web portions disposed against the web-engaging surfaces of said first assembly so that no substantial relative movement between the web portions and said web-gripping surfaces occurs;

the individual sections of at least one of said assemblies being sufiiciently spaced from one another to permit accumulation of web portions .therebetween as the opposed sections of both assemblies convergently move, the disposition of respective opposed sections being non-interdigitating;

(c) fixed means disposed bet-ween said sufiiciently spaced sections for contouring accumulated web por tions into desired configurations;

(d) means adjacent the web entry extremity for varying the spacing between the individual sections of said first assembly;

(e) means adjacent the web entry extremity for varying the spacing between the individual sections of said second assembly;

(f) means for driving said first and second assemblies substantially smoothly and in unison whereby the contoured web exits therefrom in a constant stream; and

(g) means for maintaining longitudinal tension in the exiting contoured web.

4. Continuous apparatus for forming longitudinal contours in an elongated web of material comprising:

(a) means for supporting a source of a longitudinallycontinuous web;

(b) a convex surface disposed to receive said web from said source and to change the longitudinal direction thereof as it passes thereover;

(c) opposed first and second non-interdigitating assemblies adjacent said convex surfaceand disposed to receive said web therebetween,

(1) said first assembly comprising a plurality of individual, longitudinal, convergently-movable sections with web-engaging surfaces, said sections being spaced from one another adjacent the web-entry extremity and convergent towards the web-exit extremity;

(2) said second assembly comprising a plurality of individual, longitudinal, similarly-convergently-movable sections having slip-resistant, web-gripping surfaces which bear against and frictionally grip web portions disposed against the web-engaging surfaces of said first assembly so that no substantial relative movement between the web portions and said web-gripping surfaces occurs;

the individual sections of at least one of said assemblies being sufficiently spaced from ,oneanother to permit accumulation of web portionstherebetween as theopposed sec- .tions of both assemblies convergently move, the disposition of respective opposed se i n b n onn e ig ta s; (d) fixed -means disposed between said suificiently spaced sections for contouring accumulated web portions into desired configurations;

, (e) means for-driving said first tandisecond assemblies substantially smoothly and in unison whereby the contoured web exit-s therefrom in a constant stream;

(f)- a concave surfacedisposed to receive the exiting contoureduweb and to change the longitudinal direction thereof as it passes thereover; and

(g) means for maintaining longitudinal tension in the exiting contoured web.

-5. The apparatus of claim 4 wherein said first and second assembliesare transversely curved adjacent the web entry extremity to correspond to the curvature of the Web as it leaves said convex surface, the convex curvature progressively dissipating towards the web exitextremity.

6. The apparatus of claim 5 wherein the speed of said means for driving said first and second assemblies is responsive to forces exerted on said'concave surface by the tensionedweb as it passes thereo'ver, so as to incipiently increase the speed as the forces incipiently increase and to incipiently decrease the speed as the'forces incipiently decrease.

References Cited by the Examiner UNITED STATES PATENTS 2/1 92'1 Boles 156 5 92 EARL M. BERGERT, Primary Examiner.

H. F. EPSTEIN, Assistant Examiner. 

1. CONTINUOUS APPARATUS FOR FORMING LONGITUDINAL CONTOURS IN AN ELONGATED WEB OF MATERIAL COMPRISING: (A) MEANS FOR SUPPORTING A SOURCE OF A LONGITUDINALLYCONTINUOUS WEB; (B) OPPOSED FIRST AND SECOND NON-INTERDIGITATING ASSEMBLIES DISPOSED TO RECEIVE SAID WEB THEREBETWEEN, (1) SAID FIRST ASSEMBLY COMPRISING A PLURALITY OF INDIVIDUAL, LONGITUDINAL, CONVERGENTLY-MOVABLE SECTIONS WITH WEB-ENGAGING SURFACES, SAID SECTIONS BEING SPACED FROM ONE ANOTHER ADJACENT THE WEB-ENTRY EXTREMITY AND CONVERGENT TOWARDS THE WEB-EXIST EXTREMITY; (2) SAID SECOND ASSEMBLY CONPRISING A PLURALITY OF INDIVIDUAL, LONGITUDINAL, SIMILARILY-CONVERGENTLY MOVABLE SECTIONS HAVING SLIP-RESISTANT, WEB-GRIPPING SURFACES WHICH BEAR AGAINST AND FRICTIONALLY GRIP WEB PORTIONS DISPOSED AGAINST THE WEB-ENGAGING SURFACES OF SAID FIRST ASSEMBYL SO THAT NO SUBSTANTIAL RELATIVE MOVEMENT BETWEEN THE WEB PORTIONS AND SAID WEB-GRIPPING SURFACES OCCURS; THE INDIVIDUAL SECTIONS OF AT LEAST ONE OF SAID ASSEMBLIES BEING SUFFICIENTLY SPACED FROM ONE ANOTHER TO PERMIT ACCUMULATION OF WEB PORTIONS THEREBETWEEN AS THE OPPOSED SECTIONS OF BOTH ASSEMBLIES CONVERGENTLY MOVE, THE DISPOSITION OF RESPECTIVE OPPOSED SECTIONS BEING NON-INTERDIGITATING; (C) FIXED MEANS DISPOSED BETWEEN SAID SUFFICIENTLY SPACED SECTIONS FOR CONTOURING ACCUMULATED WEB PORTIONS INTO DESIRED CONFIGURATIONS; (D) MEANS FOR DRIVING SAID FIRST AND SECOND ASSEMBLIES SUBSTANTIALLY SMOOTHLY AND IN UNISON WHEREBY THE CONTOURED WEB EXIST THEREFROM IN A CONSTANT STREAM; AND (E) MEANS FOR MAINTAINING LONGITUDINAL TENSION IN THE EXITING CONTOURED WEB. 